The number of cloth diapers you need to buy is roughly proportional to the amount you'll go through in one day. So learning that babies typically go through 3X

The number of cloth diapers you need to buy is roughly proportional to the amount you'll go through in one day. So learning that babies typically go through 3X diapers/day instead of X doesn't actually change the cloth/disposable tradeoff. That said, 30 seems high to me. Our kid probably peaked at about 8/day. (We started with cloth diapers, but the amount of time washing them was just too high.)